Table 2.

Effect of antibiotic treatment on specific bacterial organisms in preterm birth outcomes in the years 1990–2007.

Organism	Preterm birth Indicators	Association	Treatment Effect	Antibiotic(s) Prescribed	References
S. agalactiae	PTB<37 weeks	1.1 (0.9–1.4)	1.1 (0.8–1.2)	Assorted i	(63)
	LBW	1.3 (1.05–1.7)	1.0 (0.7–1.5)
			0.9 (0.6 – 1.3)	Erythromycin j	(62)
	Chorioamnionitis	7.2 (2.4–21.2)	1.2 (0.34– 4.4)	Not available	(64)
U. urealyticum	LBW b	Not reported	0.70 (0.46–1.07)	Erythromycin	(65)
				Clindamycin a
C.trachomatis	PTB	9.0, p= 0.05		Erythromycin c	(37)
	PPROM	1.3 (1.1–1.5)	0.37, p<0.01
	PTB		0.6(0.2–1.7)	Erythromycin	(84)
			0.39 (0.14–1.1)	Erythromycin	(67)
T.vaginalis	PTB		1.8 (1.2,2.7)d,f	Metronidazole	(14, 84)
			1.45(0.8–2.7)	Metronidazole	(67)
T. vaginalis + BV e		3.3 (1.01–10.7)	0.6 (0.19–1.9)	Clindamycin	(67)
		1.4 (0.4–5.5)
					(167)
T.vaginalis + C. trachomatis +BV	PTB<37 weeks	3.6 (1.8–7.5)	0.13 (0.02–1.0)	Clindamycin	(167) g
Asymptomatic bacteruria E.coli a	LBW	Not reported	0.66 (0.49–0.89)	Assorted k	(168)

^aResults of meta analysis

^bPTB outcome not measured

^cErythromycin treatment at 26 to 30 weeks. U.urealyticum colonization not associated with PTB.

^dMetronidazole treatment was not associated with increased risk of PTB at <35 or <32 weeks

^eIndividual effects not evaluated due to low numbers

^fMetronidazole treatment associated with increase in PTB

^gStudy conducted in african american women

^hHeavy colonization, defined as growth of S.agalactiae in non-selective media

ⁱAntibiotics effective against S. agalactiae - penicillins, cephalosporins, erythromycin, clindamycin, trimethoprim-sulfa, sulfisoxazole, and triple sulfa vaginal cream were used in different studies

^jTreatment during the third trimester and before 30 weeks and continuing for 10 weeks or until 35 weeks 6 days of pregnancy

^kTreatments from different studies with one of the following: nitrofurantoin,sulphadimidine, penicillin and Sulphonamides