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ARTICLE
Year : 1967  |  Volume : 15  |  Issue : 2  |  Page : 58-66

Bacterial flora in acute conjunctivitis


Department of Ophthalmology, R. G. Kar Medical College and Hospitals, Calcutta, India

Date of Web Publication18-Jan-2008

Correspondence Address:
H S Agarwala
Department of Ophthalmology, R. G. Kar Medical College and Hospitals, Calcutta
India
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Source of Support: None, Conflict of Interest: None


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How to cite this article:
Agarwala H S, Raichaudhury M, Munsi N K. Bacterial flora in acute conjunctivitis. Indian J Ophthalmol 1967;15:58-66

How to cite this URL:
Agarwala H S, Raichaudhury M, Munsi N K. Bacterial flora in acute conjunctivitis. Indian J Ophthalmol [serial online] 1967 [cited 2021 Jan 21];15:58-66. Available from: https://www.ijo.in/text.asp?1967/15/2/58/38682

Table 2

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Table 1

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Table 1

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Pinho (1942) cited pneumococcus as the commonest organism for acute conjunctivitis in U.S.A. and Koch Weeks B. was found maximum in Brazil. Sales (1942) recorded its occur­rence in 29.3% of cases in Brazil. Rodin (1945) observed staphylococci (72%), diphtheroids (52%) and stepto­cocci (12%) in all of his cases in San Francisco, but he did not find Koch Weeks B. and Morax Axenfeld B. in any of them. Soudakoff (1954) refer­red to Morax Axenfeld B. (17 to 60%) as the big offender in acute conjuncti­vitis in European countries. Pneumo­cocci (3 to 15%) and Koch Weeks B. (3 to 5%) were next in prevalence, whereas staphylococci (0 to 5%) were of least significance. Rao and Rao (1945) observed Koch Weeks B. (58.3%) and pneumococci (6.7%) as the first two bacteria of highest inci­dence in all of their cases of acute mucopurulent conjunctivitis in Mysore and found Morax Axenfeld B. and B. Xerosis (0.8%) to be in the lowermost position in their series of observations. Trachoma Control Pilot Project (T.C. P.P. 1957-58) reported Koch Weeks B. and Morax Axenfeld B. as com­monest organisms infecting conjunctiva in India.

Thus, the relative prevalence of bacteria responsible for acute conjunc­tivitis differ from place to place, even in the same country probably depend­ing on the geographical position and climate. It demands a separate investi­gation for West Bengal, as the wea­ther is very humid and the temperature never varies so widely here. Moreover, Cooper (1964) has remarked that this zone is a land of thunderstorms, and not a land of dust-storms as the rest of northern India, which latter are pro­bably responsible for greater preval­ence of trachoma and bacterial infec­tions in North-West India.


  Material and Method Top


The investigation was carried out for one year among the patients at­tending the ophthalmic out-patient de­partment of the R. G. Kar Medical College and Hospitals, Calcutta, from September 1964 to August 1965. Ma­jority of them belonged to the lower income group. A random examina­tion of, about one third of the total number of patients was carried out whenever the outdoor clinic was ope­rating.

The material for bacteriological ex­amination was taken by rubbing a sterile cotton pledget against the lower conjunctival fornix of the eye of each of the cases of untreated acute conjunc­tivitis. In a case of bilateral infection, only one eye swab for culture was taken from the more severely affected eye. Those cases in whom the infection was secondary to falling of a foreign body in the conjunctival sac or to dacryocystitis, were discarded.

The eye swab was kept in a sterile dry glass test tube and was subjected to examination within two hours. The swab after rubbing on blood agar, nu­trient agar and MacConkey's media, was finally rubbed on a glass slide for Gram's stain. After incubating the culture media aerobically at 37° C for 48 hours, the growth of the colony was watched. The bacteria growing in the colony were again subjected to Gram's stain, respective biochemical tests, and were again cultivated in special media whenever necessary. Occasionally, an agglutination test was done for final confirmation whenever required.

The curve representing percentage distribution of the total cases of acute conjunctivitis clinically seen and that of the cases where bacteriological ex­aminations were made under different age groups almost coincided [Figure - 1], showing that the bacteriologically ex­amined cases were correctly represent­ed.


  Observations Top


The average incidence of acute con­junctivitis in the year was 9.2% as 445 cases were observed among a total attendance of 4829 patients. Its occurrence went up like a step ladder from March to September (summer and rainy months) and suddenly dropped down in autumn and remained low during winter. Thus it reached its maximum 15.9% in September and minimum 4.1% in November. As seen in [Figure - 2], the monthly percentage curve of the bac­teriologically examined cases ran pa­rallel to the curve of incidence indi­cating that the observations and con­clusions would also apply to the cases which could not be examined bacteriologically.

The average humidity of each month, as well as the monthly mean temperature curves as recorded throughout the year showed a similar trend [Figure - 3],[Figure - 4].

70% of the sufferers were children and adults within the ages of 5 and 40 years. The total attendance of the patients of that age group was also 67% during the year. It was found in 262 males and 183 females, so the approximate ratio was 1.4 : 1. The average ratio of the total attendance of males and females was also 1.3 : 1.

Out of 445 cases of acute conjunc­tivitis, bacterial examination was pos­sible only in 269 cases. Out of these in 188 cases, bacterial infestation could be proved and in 81 cases the presence of bacteria could not be proved even by cultural examination. Let us call this the "no organisms" group.

The total number of sufferers and the age-wise distribution of the orga­nisms-present group and no-organisms group is shown in [Table - 1] and [Figure - 5].

It can be calculated that a single organism was found to be responsible for acute conjunctivitis in 39.4% of all sufferers, a mixed infection was present in 30.5% and no organisms could be isolated in 30% of the cases.

It was observed that the incidence of no growth of bacteria varied from 30-40% in cases in the age group from 5-60 years and it was 21% in the age group below 2 years. The age groups 2-5 years and over 60 years, presented organisms in every case [Figure - 5].

It is interesting to compare [Figure - 2],[Figure - 6], where the curves for occurrence of bracteria and no-bacteria run ex­actly opposite. Thus July to October (rainy months), are the months of maximum bacterial prevalence and minimum of non-bacterial ones. Vice versa is the case for the months of November, January.

The distribution of the different or­ganisms is shown in [Table - 2].

[Figure - 7] shows the prevalence of the different organisms throughout the year. Staph. albus was found to be the most common. 80% of them were coagulase positive and fermented mani­tol with the production of acid only. It showed peak invasion in February, and again in August, September and Octo­ber. This incidence also coincided with the seasonal invasion of Streptococci. where str. viridans had the maximum occurrence and Str. B-hoemolyticus had the least. The appearance of Str. pneumoniae in August, September was in the same proportion as that of Str. foecalis. Staph. aureus moved throughout the year in a wavy manner. St. Citreus showed higher prevalence in August and December. The inci­dence of N. Catarrhalis went up in a step ladder manner from February on­wards till it attained its acme in July, presenting a peculiar relationship with the rainfall. After that the oc­currence had a sharp fall although the rainy season continued. Koch Weeks B. had higher incidence in January, February and again in July, Septem­ber [Figure - 7].

Str. pneumoniae was mostly observed alone in conjunctiva whenever it was present. Str. citreus, Str. viridans and N. catarrhalis were mostly found mixed with other bacteria in which Staph. albus predominated. A close as­sociation between St. albus and St. citreus and the same between N. ca­tarrhalis and St. aureus were often noted. Rest of the bacteria mentioned in the list could exist by themselves or mixed with other bacteria.

[Figure - 8] shows the distribution of these organisms age-wise.

Staph. albus and N. catarrhalis were found to have minimum occurrence among young adults between the ages of 15 and 25 years. Staph. citreus was year. Staph. albus was found to be the most common. 80% of them were coagulase positive and fermented mani­tol with the production of acid only. It showed peak invasion in February, and again in August, September and Octo­ber. This incidence also coincided with the seasonal invasion of Streptococci. where str. viridans had the maximum occurrence and Str. B-hoemolyticus had the least. The appearance of Str. pneumoniae in August, September was in the same proportion as that of Str. foecalis. Staph. aureus moved throughout the year in a wavy manner. St. Citreus showed higher prevalence in August and December. The inci­dence of N. Catarrhalis went up in a step ladder manner from February on­wards till it attained its acme in July, presenting a peculiar relationship with the rainfall. After that the oc­currence had a sharp fall although the rainy season continued. Koch Weeks B, had higher incidence in January, February and again in July, Septem­ber [Figure - 7].

Str. pneumoniae was mostly observed alone in conjunctiva whenever it was present. Str. citreus, Str. viridans and N. catarrhalis were mostly found mixed with other bacteria in which Staph. albus predominated. A close as­sociation between St. albus and St. citreus and the same between N. ca­tarrhalis and St. aureus were often noted. Rest of the bacteria mentioned in the list could exist by themselves or mixed with other bacteria.

[Figure - 8] shows the distribution of these organisms age-wise.

Staph. albus and N. catarrhalis were found to have minimum occurrence among young adults between the ages of 15 and 25 years. Staph. citreus was found least among those below 2 years, and middle aged persons between 40 and 60 years. Str. pneumonia was not found in old people and Str. Facalis was not found in people over 40 and below 2 years. [Figure - 8].

Staph. albus had higher incidence on either side of the adult age group (15-25) Staph. aureus showed its maxi­mum prevalence among pre-school children between the ages of 2 and 5 years and in old persons above 60. Only children between 2 and 10 years presented Str. B-haemolyticus although fewer in number. Sir. viridans was high among babies and old people. Koch Weeks B. affected persons of all ages in an almost equal proportion [Figure - 8].

Staph. albus and Koch Weeks B. were prevalent equally in both the sexes. Staph. aureus, Sir. fmcalis, and N. catarrhalis dominated more in fe­males, whereas Str. viridans, Str. pneumonia:, Str. B-haemolyticus and Staph. citreus dominated in males.

Morax Axenfeld B., Friedlander's B. and B. subtilis were of little signi­ficance as they were found in one case each.

D. pneumonia, N. gonorrhoea, C. diphtheria and B. pyocyaneus were found in none of the cases although there were cases of acute conjunctivitis with pus and membrane formation.


  Discussion Top


It can be seen from [Figure - 2] that maximum and minimum incidences of acute conjunctivitis are in the months of September and November respectively against average incidence of 9.2%. The χ2 value for variation of percentage is 70.34 with 11 de­grees of freedom, which is greater than 19.68, a significant level for the same degree of freedom. Thereby a pro­bability of monthly variation occur­ring independently is rejected. In other words the variation of its inci­dence from month to month is statis­tically well established. However, to prove the seasonal preponderance as stated above, data covering more number of years is necessary.

While calculating the coefficient of correlation between the disease and the monthly mean temperature of Cal­cutta, the value of (statistical) 't' is 2.7149, which is a significant result and confirms the apparent relationship. But the value of `t' as found to be 1.7694, is considered non-significant with respect to the monthly mean humidity of the local atmosphere. It requires further observation. The ap­parent correlation could not be denied straight away as the rate of cases de­finitely had a tendency to rise during the rainy season, i.e., July, August and September [Figure - 2], and the largest number of positive bacterial culture reports of conjunctival swabs were also obtained during the same period [Figure - 6].

70% of the sufferers comprised of children and adults between the ages of 5 and 40 years. The apparent pre­valence of the disease more among them could not be real as about the same percentage of the total number of patients attending the hospital pre­vailed in those age groups. Similarly it was found to be almost equally prevalent in males and females.

It is argued that the mere presence of bacteria in the smears does not neces­sarily mean them to be the causative agents, for organisms can be demon­strated even in a study of normal con­junctival flora. For instance Sen (1935) also in Calcutta, found Staph. albus in 28.6%, staph. aureus in 13% and streptococci in 1.6% of cases. In his study the bacterial growth in­creased with the advent of summer and decreased with the onset of rain. This may be true in the absence of inflammation. Our study has been in inflamed eyes where the pattern of bacterial presence changes. We could get St. albus in 45.4%, St. aureus in 17.5% and streptococcus in 10.8% and the bacterial growth was maxi­mum during the rains. The change in pattern with increased infection must be taken as the cause of the increased incidence. Where a single organism can be cultured in large numbers of colonies the cause can never be doubted.

Staphylococci were the commonest; bacteria and found in 85.6% of cases if only positive bacterial culture reports were considered. Moreover, they were also found in cases of pseudo-mem­branous conjunctivitis, where the suf­ferers were babies of about two years of age. Thygeson and Braley (1943) have reported that staphylococcic con­junctivitis is resistant to ordinary che­mical antiseptics and easily gets chronic. Duke Elder (1965) mentions sulphonamides are of rare value. In our experience, Penicillin is ineffec­tive in many cases, and in the form of ointment produces much ocular irrita­tion in a large number of patients as a result of tissue hypersensitivity. Any broad spectrum antibiotic after testing individual sensitivity is a better form of treatment than the routine use of Gutta Mercurochrome or Protargol.

Although Wilson and Miles (1957) differentiate between coagulase po­sitive and negative staph. albus, the latter which are non-pathogenic may undergo mutation and acquire patho­genicity with changes in environment -Duke Elder (1965). Hence, for better understanding on morphologi­cal grounds, both coagulase positive and negative varieties of albus are in­cluded negative the group of staph. albus. Thus staph. albus occupying the high­est position in the list, its peak inva­sions coincide with those of strepto­cocci [Figure - 7]. Therefore due consi­deration for pathogenicity should be given to it, irrespective of its coagu­lase reaction, while considering the swab reports prior to operation.

Staph. citreus and N. catarrhalis were mostly found in association with other bacteria. Specific solitary exist­ence of Staph. citreus was rare. Bhaduri (1945) reported the cases of Staph. citreus conjunctivitis as chronic and associated with multiple nodules with pus points on them in the con­junctiva. No such case was found here as the cases were of very recent origin.

Gupta and Preobragenski (1964) have remarked that secondary bac­terial conjunctivitis prolongs the pat­tern and the course of trachoma. Trachoma without secondary infection often gets spontaneous cure with mini­mal scarring. Incidence of trachoma in north India (16 to 79%) is very high as against Bengal (0.5%). Infec­tion of conjunctiva by Koch Weeks B. and Morax Axenfeld B. is also very high in North West India. Similar raised incidence of Koch Weeks B. and Morax Axenfeld B. in trachoma­tous conjunctivitis was also observed by T.C.P.P.-India, 1957-58 (cited by Nema et al 1964). Further, in South India, trachoma is recorded maximum (22%) in Mysore. Rao and Rao (1945) have observed Koch Weeks B. having maximum prevalence (58%) in My­sore, in cases of acute mucopurulent conjunctivitis. In this part of the country, low invasion of Koch Weeks B and Morax Axenfeld B. might be an explanation for such low incidence of trachoma.

But Nema et al (1964) differed wide­ly from the finding of T.C.P.P. They observed rather a very low incidence of Koch Weeks B. and Morax Axenfeld B. in trachomatous conjunctivitis in north west India. It appears that fur­ther work is needed to determine the contributing role of these bacteria, if any, in trachoma and its severity.

Soudakoff (1954) mentions that the cases of acute conjunctivitis revealed no growth of bacteria on culture to the extent of 31% at Freiburg, 28% at Lausanne, 30% at Coppenhagen and 16% at Glasgow. He states that ne­gative results depend to a certain extent upon the technique employed and they do not exclude virus and rickettsia infections. Our figure, 30% of no growth, corroborates with their findings.

Dhurandhar and Maskati (1954) observed in summer months maxi­mum occurence of a peculiar type of acute catarrhal conjunctivitis with preauricular lymphadenopathy of 2-3 weeks duration among 15-25 years age group. They were probably of viral origin as they presented no growth of bacteria on culture and topical use of cortisone drops re­markably shortened the course of the disease to one week. Our figure of no growth was also maximum in the age group 15-25 years [Figure - 5]. But it occurred mostly in winter months [Figure - 6]. The course of the disease and other features were not followed up. They might have been viral, but this does not exclude the possibility of allergy or some other infection.


  Summary Top


The average incidence of acute conjunctivitis was 9.2%. Its occurence was high in summer and rainy season, and low in winter. It affected people of all ages, and both the sexes more or less equally.

70%, of the conjunctival swabs re­vealed the presence of bacteria. But swabs taken from pre-school children between 2 and 5 years and from old people above 60 years presented bac­teria in every case. Bacterial preval­ence increased in large number in August and September.

The relative incidence of the dif­ferent pathogenic organisms is worked out and tabulated.


  Acknowledgement Top


Our thanks are due to D. A. K. Pal, assistant professor of preventive and social medicine, R. G. Kar Medi­cal College, for his suggestions and help in carrying out the statistical part of the work.[14]

 
  References Top

1.
Bhaduri, B. N. (1945), Proc. All-India Ophth. Soc. 8: 58-60.  Back to cited text no. 1
    
2.
Cooper, S. N. (1964), J1. All-India Ophth. Soc. 12: 50-58.  Back to cited text no. 2
    
3.
Dhurandhar C. B. and Maskati B. T. (1954) J. All-India Ophthal. Soc. 1: 103.  Back to cited text no. 3
    
4.
Duke Elder, W. S. (1965). System of Ophthalmology, London. Kimpton, v. 8. (Pt. 1.), p. 158.  Back to cited text no. 4
    
5.
Gupta, U. C. and Preobragenski, V. V. (1964). Jl. of All-India Ophth. Soc. 12: 39-49.  Back to cited text no. 5
    
6.
Nema, H. V., Bal. A., Nath, K., Shukla, B. R. (1964). Brit. JI. Ophth. 48: 690-691.  Back to cited text no. 6
    
7.
Pinho, E. (1942), Arquivos Brasileiros de Ophthalmologia 5: 190-193.  Back to cited text no. 7
    
8.
Rao. S. V. and Rao, M.B.S. (1945), Proc. All India Ophth. Soc. 8: 53-57.  Back to cited text no. 8
    
9.
Rodin, F. H. (1945). Amer. J. Ophthal. 28: 306-314.  Back to cited text no. 9
    
10.
Sales, M. (1942), Arquivos de Inst. Penido Burnier, 6: 390-414.  Back to cited text no. 10
    
11.
Sen K. (1935), Proc. All-India Ophth. Soc. 4, 223-225.  Back to cited text no. 11
    
12.
Soudakoff, P. S. (1954), Amer. J. Ophthal. 38: 374-376.  Back to cited text no. 12
    
13.
Thygeson, P. and Braley, A. E. (1943), Arch. of Ophth. 29: 760-766.  Back to cited text no. 13
    
14.
Wilson G. S. and Miles A. A. (1957), Topley and Wilson's Principles of Bacteriology and Immunity, 4th edition. Erward Arnold (Publ.). London Vol. 1. p. 714-715.  Back to cited text no. 14
    


    Figures

  [Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5], [Figure - 6], [Figure - 7], [Figure - 8]
 
 
    Tables

  [Table - 1], [Table - 2]



 

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